Electric-arc lamp.



F. R., R. V. 6L F. BOARDIVIAN.

ELECTRIC ARC LAMP.

APPLICATION FILED DEC. I7. I9I3.

Patented Mar. 26, 1918.

3 SHEETS-SHEET l.

F. R., R. V. L F. BOARDMAN.

ELECTRIC ARC LAMP.

M'PLlcATloN FlLED [150.17.1913.

Patented Mar. 26, 1918.

3 SHEETS-SHEET 2.

lcL R., R. V. 6L F. BOARDMAN.

ELECTRIC ARG LAMP.

APPLICATION FILED DEC. 17, 1913.

1,260,747. Patented Mar. 26, 1918.

3 SHEETS-SHEET 3| UNITED sTATEs PATENT oEEIcE.A

FREDERICK n. BOAKDMAN, RICHARD v. BCAEDMAN, AND FRANK BCAEDMAN, or

UPToN PARK, ENGLAND.

ELECTRIC-Anc LAMP.

of Essex, Kingdom of England, have invented certain new and useful Improvements in Electric-Arc Lamps, of which the following is a specification.

This invention relates to improvements in electric arc focusing" lamps of the open arc type and particularly of the kind in which a plurality of pairs of carbons are employed in each lamp and connected up in series and the lamps may be connected leitherin serles or in parallel as may be desired.-

This invention has for its object to provide means whereby each carbon of all the pairs of carbons will be quickly and simultaneously fed forward as soon as the pull of the series or other regulating coil becomes weak due to any one or all of the pairs of the carbons being consumed thereby'insuring the effective readjustment of all the arcs at intervals and rendering such lamps suitable for burning for long periods at a time without attention as is required for certain purposes.

In multiple carbon arc lamps of the inclosed type it has heretofore been proposed to provlde the movable ,carbonpof each pair of carbons with an independent clutch and to control all of the clutches by a common regulating magnet the coil of which is adapted to be partly short circuited so as to .materially weaken its power when its core vreaches a determinate position and thereby cause all the carbons to be fed simultaneously as all the clutches are released.

The present invention is chieliy distinguished from such arrangement in that an additional auxiliary shunt coil is provided which acts upon a core, preferably common to the main regulating coil, and is only momentarily brought into operation upon the movement of the regulating means by a one-way switch,

The invention in one of its simplest forms is hereinafter shown in, and described with reference to, the accompanying drawings in which:` l

Specication of Letters Patent.

Patented Mar. 26, 1918.

Application led December 17, 1913. Serial No. 807,168.

Figure 1 is a detail side elevation of the upper part of a lamp embodying our improvements;

Fig 2 is a sectional plan view of the device taken on the line 2-2 of Fig. 1.

Fig. 3 is a diagrammatic view of the complete lamp. Y

Fig. 4 1s a diagram ofthe circuit in the preferred form of the device, and Fig. 5 is a similar view of a modified form.

-In the particular construction of lamp shown' having four pairs of carbons a two disks or plates b, c are connected together by four brass pillars ci to form the frame of the lamp. Cross pieces e are mounted between thc front pillars d to carry the pulley wheels f over which chains g supporting the upper and lower carbon holder supporting rods are arranged. The guides h for the tgp carbon holder supporting rods are ins ated from the disk or plate c as at c. The lower carbon holder supporting rods c are formed of pieces of squaretube (for lightness) and the bracket i upon the lowerl extremity is'insulated as at z' therefrom in the known manner. The square tubes i pass through suitable square guides on the lamp frame and at the top are attached to the above referred to pieces of brass chain or the like g which pass over the aforesaid pulleys f and are connected to the too carbon holder supporting rod j these connections being suitably insulated as indicated at j from the 'top carbon holders. The top carbon holder supporting `rods j are preferably weighted so as to be heavy enough to pull the lower rods i up. Between the two front pillars Z a striking lever frame ,7c is pivoted at lo. This frame comprises a bar k2 trunnioned at its ends to the pillars d, a parallel bar k3 and a pair of connecting members 7a4. Fixed to said frame is an arm Z to the free end of whichris attached the core of 'solenoid m and a dashpot plunger n.5 The solenoid coil is in the present instance formed partly as a series coil o and partly as a shunt wound coil p and both are together suspended from the top disk or plate b. The

aforesaid lever frame lo carries the four l i to fau, and thus the am is formed. These are preferably connected to the bar les as by hin edly connected links g.

ow by the present invention a flexible contact arm 7' is insulated as at t from and carried by the striking lever or frame k in such a position that it moves in the ath of another iiexible contact arm s suitab y supported from and insulated as at u from the the frame e. The arm r carries on its upper end an insulating block or pad 1" and also the arm s carries a similar block or pad s on its lower side so that when the arm r is in the lowest position and brushes upward past the arm .s no electrical contact is made between the two arms r and s form` ing the switch as electrical Contact has only to be established upon movement of the arm r in a downward direction.

The switch o erates during the working of the lamp as ollows When current is switched on the iron core m is drawn up by means of the series coil o and the switch arms 1' and s merely brush past each other without making electrical contact with one another. As however one or all of the pairs of carbons consume, the `pull of theseries coil becomes weaker and the striking frame It gradually falls and maintains a practically constant arc until the switch arm r establishes electrical connection with the fixed arm s and momentarily puts the shunt coil pv in action to cause the se arate pairs of carbons to simultaneously eed together 'or meet. The downward pull of the shunt coil also breaks its own circuit by pullin the arm r down below the arm s as will e readily understood by reference to the drawings. The pull of the series coil then naturally increases and pulls up the core m to strike the arc as before.

In the case of, a lamp for use on alternating currents the series and shunt coils o and p respectively, where such are employed, would as shown in Fig. 5, preferably be separated from one another and the iron core m would be divided into two parts m and m2 which would be separated from each other by an intermediate iece of insulating material ma. The spoo s containing the series and shunt windings would also preferably be divided as shown at m4 to prevent eddy currents and the coils which are insulated from the disks and plates of the lamp being also insulated from each other, will to a large extent prevent an induced current being generated in either of the said coils.

The various electrical connections both for the switch and for the carbons may be made by flexible wires in any well-known manner according to requirements.

What we claim as our invention and desire to secure by Letters Patent of the United States is 1. In a device of the class described, a plurality of pairs of carbons, a swinging frame, clutches on said frame normally engaging the upper carbon of each pair, electromagnetic means in series with said carbons normall exerting an upward pull on said frame to li tthe same,electromagnetic means shunted to said carbons and adapted when energized to swing said frame downwardly and a one way switch for momentarily closing the circuit of the second mentioned electromagnetic means upon an initial drop of said frame, substantially as described.

2. In a device of the class described, a plurality of pairs of carbons, a swinging frame, clutches on said frame normally engaging the upper carbon of each pair, electromagnetic means in series with said carbons and normally exerting an upward pull on said frame to lift the same, electromagnetic means shunted to said carbons andadapted when ener ized to swing said frame downwardly an a one way switch comprisin a fixed contact member and a contact mem er on said swinging frame, adapted to momentarily close the circuit of the second mentioned electromagnetic means upon an initial drop of said frame, substantially as described. i

3. In a device of the class described, a plurality of pairs of carbons, a swinging frame, clutches on said frame normally engaging the upper carbon of each pair, electromagnectic means in series with said carbons and normally exerting an upward pull on said frame to lift the same, electromagnetic means shunted to said carbons and adapted when energized to swing said frame downwardly an a one way switch comprising a fixed contact member and a contact member on said swin ing frame, insulating members on the un er face of the end of said fixed contact member and on the upper face of the end of the contact member on the swinging frame whereby the circuit to the second mentioned electromagnetic means is momentarily closed upon an initial drop of said frame ut remains o en as the contacts pass upon the raisin o said frame, substantially as describe l In testimony whereof we have signed this specification in the presence of two subscribing witnesses.

F. R. BOARDMAN. R, v. BOARDMAN. F. BOARDMAN.

Witnesses to the annexed three signatures:

J. C. WITHERS, FRANK BLAKEY. 

